Adhesives having improved chemical resistance and curable silicone compositions for preparing the adhesives

ABSTRACT

This invention relates to a composition that can be cured to form an adhesive. The adhesive is useful in the electronics industry. The composition is prepared by mixing components including:
         (I) a polyorganosiloxane having an average of at least two terminally-unsaturated organic groups per molecule,   (II) an organohydrogenpolysiloxane having an average of at least two silicon-bonded hydrogen atoms per molecule,   (III) a hydrosilylation catalyst,   (IV) a fluoroorganosilicone having at least one functional group reactive with component (I), component (II), or both,   (V) an unsaturated ester-functional compound, and   (VI) an adhesion promoter.
 
The composition may also include one or more optional components selected from (VII) a void reducing agent, (VIII) a pigment, (IX) a filler, (X) a cure modifier, (XI) a rheology modifier, and (XII) a spacer.

CROSS REFERENCE

This application is a continuation in part of U.S. patent applicationSer. No. 10/641,758, filed on 14 Aug. 2003 now U.S. Pat. No. 7,045,586and claims priority thereto under 35 U.S.C. § 120 and 35 U.S.C. §365(c).U.S. patent application Ser. No. 10/641,758 is hereby incorporated byreference.

FIELD OF THE INVENTION

This invention relates to curable silicone compositions and productsformed by curing the curable silicone compositions. More particularly,this invention relates to hydrosilylation-curable compositions that cureto form products having improved adhesion and chemical resistance.

BACKGROUND OF THE INVENTION

Plastics containing low surface energy polymers, e.g., blends of Nylonand syndiotactic polystyrene (sPS), are seeing growing acceptance as areplacement for denser, hygroscopic plastics such aspolybutyleneterephthalate (PBT) and Nylon as substrates in highperformance applications such as those found in the electronics andautomotive industries. For example, existing adhesives used in theelectronics industry suffer from the drawback of having poor adhesion tosubstrates containing syndiotactic polystyrene. Therefore, there is aneed for developing adhesives having improved adhesion to substratescontaining sPS while retaining adhesion to a variety of other organicand inorganic substrates.

Furthermore, polyorganosiloxane elastomer adhesives, such aspolydimethylsiloxane-based elastomers, are frequently used in theelectronics industry for properties such as their thermal stability andability to relieve stresses over a broad thermal range. However, theseadhesives may suffer from the drawback of poor resistance to someorganic chemicals, such as solvents and engine oils. Fluorosiliconeelastomers and organic elastomers have been used to improve chemicalresistance. However, fluorosilicone elastomers suffer from the drawbackof having higher cost than polyorganosiloxane elastomers (that arenon-fluorinated). One proposed approach to address this is to combinefluorosilicone elastomers with polyorganosiloxane elastomers. However,proposed approach has generally not been used due to concerns that thefluorosilicone and non-fluorinated organosilicone components would phaseseparate, resulting in unstable properties. Organic elastomers maysuffer from the drawback of having insufficient flexibility or bulkthermal properties. Therefore, there is a need in the electronicsindustry for adhesives having improved chemical resistance whileretaining flexibility and bulk thermal properties.

SUMMARY OF THE INVENTION

This invention relates to a composition prepared by mixing componentscomprising:

-   -   (I) a polyorganosiloxane having an average of at least two        unsaturated organic groups per molecule,    -   (II) an organohydrogenpolysiloxane having an average of at least        two silicon-bonded hydrogen atoms per molecule,    -   (III) a hydrosilylation catalyst,    -   (IV) a fluoroorganosilicone having at least one functional group        reactive with component (I), component (II), or both,    -   (V) an unsaturated ester-functional compound, and    -   (VI) an adhesion promoter.        Component (I) is free of fluorine atoms. Component (II) is free        of fluorine atoms.

DETAILED DESCRIPTION OF THE INVENTION

All amounts, ratios, and percentages are by weight unless otherwiseindicated. The following is a list of definitions, as used herein.

DEFINITIONS AND USAGE OF TERMS

“A” and “an” each mean one or more.

“Chemical resistance” means reduced tendency of a silicone elastomer toswell, or degrade, or both, when exposed to solvents and oils.

“Combination” means two or more items put together by any method.

The abbreviation “cP” means centipoise.

The abbreviation “IR” means infrared.

“Pa.s” means Pascal seconds.

The abbreviation “ppm” means parts per million.

“Silicone” and “siloxane” are used interchangeably herein.

This invention relates to a composition prepared by mixing componentscomprising:

-   -   (I) a polyorganosiloxane having an average of at least two        unsaturated organic groups per molecule,    -   (II) an organohydrogenpolysiloxane having an average of at least        two silicon bonded hydrogen atoms per molecule,    -   (III) a hydrosilylation catalyst,    -   (IV) a fluoroorganosilicone having at least one functional group        reactive with component (I), component (II), or both,    -   (V) an unsaturated ester-functional compound, and    -   (VI) an adhesion promoter.

Component (I) Polyorganosiloxane

Component (I) is a polyorganosiloxane having an average of at least twounsaturated organic groups per molecule. Component (I) may have alinear, branched, or resinous structure. Component (I) may be ahomopolymer or a copolymer. The unsaturated organic groups may bealkenyl groups having from 2 to 12 carbon atoms and are exemplified by,but not limited to, vinyl, allyl, butenyl, and hexenyl. The unsaturatedorganic groups may be alkynyl groups having 2 to 12 carbon atoms, andare exemplified by, but not limited to, ethynyl, propynyl, and butynyl.Alternatively, the unsaturated organic groups may containacrylate-functional or methacrylate-functional groups and areexemplified by, but not limited to, acryloyloxyalkyl such asacryloyloxypropyl and methacryloyloxyalkyl such asmethacryloyloxypropyl. The unsaturated organic groups in component (I)may be located at terminal, pendant, or both terminal and pendantpositions.

The remaining silicon-bonded organic groups in component (I) may bemonovalent organic groups free of aliphatic unsaturation. Thesemonovalent organic groups may have 1 to 20 carbon atoms, alternatively 1to 10 carbon atoms, and are exemplified by, but not limited to alkylsuch as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl;cycloalkyl such as cyclohexyl; aryl such as phenyl, tolyl, xylyl,benzyl, and 2-phenylethyl; and cyano-functional groups such ascyanoalkyl groups exemplified by cyanoethyl and cyanopropyl. Component(I) is free of fluorine atoms.

The viscosity of component (I) is not specifically restricted, however,component (I) may have a viscosity of 0.05 to 500 Pa.s at 25° C.,alternatively 0.1 to 200 Pa.s at 25° C. Component (I) is added to thecomposition in an amount of 100 weight parts. Component (I) may comprisea polyorganosiloxane of the formula(a) R¹ ₃SiO(R¹ ₂SiO)_(α)(R¹R²SiO)_(β)SiR¹ ₃,(b) R³ ₂R⁴SiO(R³ ₂SiO)_(χ)(R³R⁴SiO)_(δ)SiR³ ₂R⁴, or

-   (c) a combination thereof.

In formula (a), α has an average value of 0 to 2000, and β has anaverage value of 2 to 2000. Each R¹ is independently a monovalentorganic group. Suitable monovalent organic groups include, but are notlimited to, acrylic functional groups such as acryloyloxypropyl andmethacryloyloxypropyl; alkyl groups such as methyl, ethyl, propyl, andbutyl; alkenyl groups such as vinyl, allyl, and butenyl; alkynyl groupssuch as ethynyl and propynyl; aromatic groups such as phenyl, tolyl, andxylyl; and cyanoalkyl groups such as cyanoethyl and cyanopropyl. Each R²is independently an unsaturated monovalent organic group. R² isexemplified by alkenyl groups such as vinyl, allyl, and butenyl andalkynyl groups such as ethynyl and propynyl, and acrylic functionalgroups such as acryloyloxypropyl and methacryloyloxypropyl.

In formula (b), χ has an average value of 0 to 2000, and δ has anaverage value of 0 to 2000. Each R³ is independently a monovalentorganic group. Suitable monovalent organic groups include, but are notlimited to, acrylic functional groups such as acryloyloxypropyl andmethacryloyloxypropyl; alkyl groups such as methyl, ethyl, propyl, andbutyl; alkenyl groups such as vinyl, allyl, and butenyl; alkynyl groupssuch as ethynyl and propynyl; aromatic groups such as phenyl, tolyl, andxylyl; and cyanoalkyl groups such as cyanoethyl and cyanopropyl. Each R⁴is independently an unsaturated organic hydrocarbon group. R⁴ isexemplified by alkenyl groups such as vinyl, allyl, and butenyl; alkynylgroups such as ethynyl and propynyl; and acrylic functional groups suchas acryloyloxypropyl and methacryloyloxypropyl.

Component (I) may comprise polydiorganosiloxanes such as

-   i) dimethylvinylsiloxy-terminated polydimethylsiloxane,-   ii) dimethylvinylsiloxy-terminated    poly(dimethylsiloxane/methylvinylsiloxane),-   iii) dimethylvinylsiloxy-terminated polymethylvinylsiloxane,-   iv) trimethylsiloxy-terminated    poly(dimethylsiloxane/methylvinylsiloxane),-   v) trimethylsiloxy-terminated polymethylvinylsiloxane,-   vi) dimethylvinylsiloxy-terminated    poly(dimethylsiloxane/methylphenylsiloxane),-   vii) dimethylvinylsiloxy-terminated    poly(dimethylsiloxane/diphenylsiloxane),-   viii) phenyl,methyl,vinyl-siloxy-terminated polydimethylsiloxane,-   ix) dimethyl-acryloyloxypropyl-siloxy-terminated    polydimethylsiloxane,-   x) dimethyl-methacryloyloxypropyl-siloxy-terminated    polydimethylsiloxane,-   xi) dimethylhexenylsiloxy-terminated polydimethylsiloxane,-   xii) dimethylhexenylsiloxy-terminated    poly(dimethylsiloxane/methylhexenylsiloxane),-   xiii) dimethylhexenylsiloxy-terminated polymethylhexenylsiloxane,-   xiv) trimethylsiloxy-terminated    poly(dimethylsiloxane/methylhexenylsiloxane),-   xv) dimethylvinylsiloxy-terminated    poly(dimethylsiloxane/methylcyanopropylsiloxane), and-   xvi) combinations thereof.

Methods of preparing polydiorganosiloxanes suitable for use as component(I), such as hydrolysis and condensation of the correspondingorganohalosilanes or equilibration of cyclic polydiorganosiloxanes, arewell known in the art.

Component (I) may comprise resins such as an MQ resin consistingessentially of R⁵ ₃SiO_(1/2) units and SiO_(4/2) units, a TD resinconsisting essentially of R⁵SiO_(3/2) units and R⁵ ₂SiO_(2/2) units, anMT resin consisting essentially of R⁵ ₃SiO_(1/2) units and R⁵SiO_(3/2)units, an MTD resin consisting essentially of R⁵ ₃SiO_(1/2) units,R⁵SiO_(3/2) units, and R⁵ ₂SiO_(2/2) units, or a combination thereof.

Each R⁵ is a monovalent organic group. The monovalent organic groupsrepresented by R⁵ may have 1 to 20 carbon atoms, alternatively 1 to 10carbon atoms. Examples of monovalent organic groups include, but are notlimited to, acrylate functional groups such as acryloxyalkyl groups,methacrylate functional groups such as methacryloxyalkyl groups,cyano-functional groups, and monovalent hydrocarbon groups. Monovalenthydrocarbon groups include, but are not limited to, alkyl such asmethyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkylsuch as cyclohexyl; alkenyl such as vinyl, allyl, butenyl, and hexenyl;alkynyl such as ethynyl, propynyl, and butynyl; and aryl such as phenyl,tolyl, xylyl, benzyl, and 2-phenylethyl. Cyano-functional groupsinclude, but are not limited to cyanoalkyl groups such as cyanoethyl andcyanopropyl.

The resin may contain an average of 3 to 30 mole percent of unsaturatedorganic groups. The unsaturated organic groups may be alkenyl groups,alkynyl groups, acrylate-functional groups, methacrylate-functionalgroups, or combinations thereof. The mole percent of unsaturated organicgroups in the resin is the ratio of the number of moles of unsaturatedgroup-containing siloxane units in the resin to the total number ofmoles of siloxane units in the resin, multiplied by 100.

Methods of preparing resins are well known in the art. For example,resin may be prepared by treating a resin copolymer produced by thesilica hydrosol capping process of Daudt et al. with at least analkenyl-containing endblocking reagent. The method of Daudt et al., isdisclosed in U.S. Pat. No. 2,676,182.

Briefly stated, the method of Daudt et al. involves reacting a silicahydrosol under acidic conditions with a hydrolyzable triorganosilanesuch as trimethylchlorosilane, a siloxane such as hexamethyldisiloxane,or mixtures thereof, and recovering a copolymer having M and Q units.The resulting copolymers generally contain from 2 to 5 percent by weightof hydroxyl groups.

The resin, which typically contains less than 2 percent by weight ofsilicon-bonded hydroxyl groups, may be prepared by reacting the productof Daudt et al. with an unsaturated organic group-containing endblockingagent and an endblocking agent free of aliphatic unsaturation, in anamount sufficient to provide from 3 to 30 mole percent of unsaturatedorganic groups in the final product. Examples of endblocking agentsinclude, but are not limited to, silazanes, siloxanes, and silanes.Suitable endblocking agents are known in the art and exemplified in U.S.Pat. Nos. 4,584,355; 4,591,622; and 4,585,836. A single endblockingagent or a mixture of such agents may be used to prepare the resin.

Component (I) can be a single polyorganosiloxane or a combinationcomprising two or more polyorganosiloxanes that differ in at least oneof the following properties: structure, viscosity, average molecularweight, siloxane units, and sequence.

Component (II) Organohydrogenpolysiloxane

Component (II) is an organohydrogenpolysiloxane having an average of atleast two silicon-bonded hydrogen atoms per molecule. Component (II) canbe can be a homopolymer or a copolymer. Component (II) can have alinear, branched, cyclic, or resinous structure. The silicon-bondedhydrogen atoms in the component (II) can be located at terminal,pendant, or at both terminal and pendant positions. Component (II) isfree of fluorine atoms.

Component (II) can comprise siloxane units including, but not limitedto, HR⁶ ₂SiO_(1/2), R⁶ ₃SiO_(1/2), HR⁶SiO_(2/2), R⁶ ₂SiO_(2/2),R⁶SiO_(3/2), and SiO_(4/2) units. In the preceding formulae, each R⁶ isindependently selected from monovalent organic groups free of aliphaticunsaturation.

Component (II) may comprise a compound of the formula(a) R⁷ ₃SiO(R⁷ ₂SiO)_(ε)(R⁷HSiO)_(φ)SiR⁷ ₃, orR⁸ ₂HSiO(R⁸ ₂SiO)_(γ)R⁸HSiO)_(η)SiR⁸ ₂H,

-   (c) a combination thereof.

In formula (a), ε has an average value of 0 to 2000, and φ has anaverage value of 2 to 2000. Each R⁷ is independently a monovalentorganic group free of aliphatic unsaturation. Suitable monovalentorganic groups free of aliphatic unsaturation include alkyl groups suchas methyl, ethyl, propyl, and butyl; aromatic groups such as phenyl,tolyl, and xylyl; and cyano-functional groups exemplified by cyanoalkylgroups such as cyanoethyl and cyanopropyl.

In formula (b), γ has an average value of 0 to 2000, and η has anaverage value of 0 to 2000. Each R⁸ is independently a monovalentorganic group free of aliphatic unsaturation. Suitable monovalentorganic groups free of aliphatic unsaturation include alkyl groups suchas methyl, ethyl, propyl, and butyl; aromatic groups such as phenyl,tolyl, and xylyl; and cyano-functional groups exemplified by cyanoalkylgroups such as cyanoethyl and cyanopropyl.

Component (II) is exemplified by

-   i) dimethylhydrogensiloxy-terminated polydimethylsiloxane,-   ii) dimethylhydrogensiloxy-terminated    poly(dimethylsiloxane/methylhydrogensiloxane),-   iii) dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane,-   iv) trimethylsiloxy-terminated    poly(dimethylsiloxane/methylhydrogensiloxane),-   v) trimethylsiloxy-terminated polymethylhydrogensiloxane,-   vi) a resin consisting essentially of H(CH₃)₂SiO_(1/2) units and    SiO_(4/2) units, and-   vii) combinations thereof.

Component (II) can be a combination of two or moreorganohydrogenpolysiloxanes that differ in at least one of the followingproperties: structure, average molecular weight, viscosity, siloxaneunits, and sequence.

Methods of preparing linear, branched, and cyclicorganohydrogenpolysiloxanes suitable for use as component (II), such ashydrolysis and condensation of organohalosilanes, are well known in theart. Methods of preparing organohydrogenpolysiloxane resins suitable foruse as component (II) are also well known as exemplified in U.S. Pat.Nos. 5,310,843; 4,370,358; and 4,707,531.

The molar ratio of silicon-bonded hydrogen atoms in component (B) toaliphatically unsaturated groups in component (A) (SiH_(B)/Vi_(A)) isnot critical.

Component (III) Hydrosilylation Catalyst

Component (III) is a hydrosilylation catalyst. Component (III) is addedto the composition in an amount of 0.1 to 1000 ppm of platinum groupmetal, alternatively 1 to 500 ppm, alternatively 2 to 200, alternatively5 to 150 ppm, based on the weight of the composition. Suitablehydrosilylation catalysts are known in the art and commerciallyavailable. Component (III) may comprise a platinum group metal selectedfrom platinum, rhodium, ruthenium, palladium, osmium or iridium metal ororganometallic compound thereof, or a combination thereof. Component(III) is exemplified by compounds such as chloroplatinic acid,chloroplatinic acid hexahydrate, platinum dichloride, and complexes ofsaid compounds with low molecular weight organopolysiloxanes or platinumcompounds microencapsulated in a matrix or coreshell type structure.Complexes of platinum with low molecular weight organopolysiloxanesinclude 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane complexes withplatinum. These complexes may be microencapsulated in a resin matrix.

Suitable hydrosilylation catalysts for component (III) are described in,for example, U.S. Pat. Nos. 3,159,601; 3,220,972; 3,296,291; 3,419,593;3,516,946; 3,814,730; 3,989,668; 4,784,879; 5,036,117; and 5,175,325 andEP 0 347 895 B. Microencapsulated hydrosilylation catalysts and methodsof preparing them are known in the art, as exemplified in U.S. Pat. No.4,766,176 and the references cited therein; and U.S. Pat. No. 5,017,654.

Component (IV) Fluoroorganosilicone

Component (IV) is a fluoroorganosilicone having at least one functionalgroup reactive with component (I), component (II), or both. Theviscosity of component (IV) is not specifically restricted, however,component (IV) may have a viscosity of 0.0001 to 500 Pa.s at 25° C.

Component (IV) may comprise a compound of the formula:(a) R⁹ ₃SiO(R⁹ ₂SiO)_(τ)(R⁹R¹⁰SiO)_(φ)SiR⁹ ₃,(b) R¹¹ ₂R¹²SiO(R¹¹ ₂SiO)_(κ)(R¹¹R¹²SiO)_(λ)SiR¹¹ ₂R¹²,(c) F₃C(CF₂)_(ν)R¹³—Si—[O—Si(R¹⁴)₂(R¹⁵)]₃,

-   (d) a resinous or branched structure consisting essentially of    R¹⁵R¹⁴ ₂SiO_(1/2) units, CF₃(CF₂)_(ν)R¹³SiO_(3/2) units, and    optionally SiO_(4/2) units, or-   (e) a combination thereof.

In formula (a) τ has an average value of 0 to 2000, and φ has an averagevalue of 1 to 500. Each R⁹ is independently a hydrogen atom or amonovalent organic group. Suitable monovalent organic groups includemonovalent hydrocarbon groups that are free of aliphatic unsaturationsuch as alkyl groups such as methyl, ethyl, propyl, and butyl; aromaticgroups such as phenyl, tolyl, and xylyl; and cyano-functional groupsexemplified by cyanoalkyl groups such as cyanoethyl and cyanopropyl.Suitable monovalent organic groups also include unsaturated monovalentorganic groups exemplified by acrylate functional groups; methacrylatefunctional groups; alkenyl groups such as vinyl, allyl, and butenyl; andalkynyl groups such as ethynyl, propynyl, and butynyl. In formula (a) atleast one R⁹ is a hydrogen atom or an unsaturated monovalent organicgroup. Each R¹⁰ is independently a fluoro-functional organic group.Suitable fluoro-functional organic groups include, but are not limitedto, fluorinated alkyl groups such as 3,3,3-trifluoropropyl,4,4,4,3,3-pentafluorobutyl, 5,5,5,4,4,3,3-heptafluoropentyl, and6,6,6,5,5,4,4,3,3-nonafluorohexyl.

In formula (b) κ has an average value of 0 to 2000, and λ has an averagevalue of 0 to 500. Each R¹¹ is independently a hydrogen atom or amonovalent organic group. Suitable monovalent organic groups includecyano-functional groups exemplified by cyanoalkyl groups such ascyanoethyl and cyanopropyl; and monovalent hydrocarbon groups free ofaliphatic unsaturation, exemplified by alkyl groups such as methyl,ethyl, propyl, and butyl; and aromatic groups such as phenyl, tolyl, andxylyl. Suitable monovalent organic groups also include unsaturatedmonovalent organic groups exemplified by acrylate functional groups;methacrylate functional groups; alkenyl groups such as vinyl, allyl, andbutenyl; and alkynyl groups such as ethynyl, propynyl, and butynyl. Informula (b) at least one R¹¹ is a hydrogen atom or an unsaturatedmonovalent organic group. Each R¹² is independently a fluoro-functionalorganic group. Suitable fluoro-functional organic groups includefluorinated alkyl groups such as 3,3,3-trifluoropropyl,4,4,4,3,3-pentafluorobutyl, 5,5,5,4,4,3,3-heptafluoropentyl, and6,6,6,5,5,4,4,3,3-nonafluorohexyl.

In formulae (c) and (d), ν is 0 to 10. Each R¹³ is independently adivalent organic group such as a divalent hydrocarbon group. Suitabledivalent organic groups for R¹³ may have at least 2 carbon atoms,alternatively, 2 to 20 carbon atoms, alternatively 2 to 10 carbon atoms.Examples of suitable divalent hydrocarbon groups for R¹³ includealkylene groups such as methylene, ethylene, propylene, and butylene.Each R¹⁴ is independently a monovalent hydrocarbon group free ofaliphatic unsaturation. R¹⁴ is exemplified by alkyl such as methyl,ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl such ascyclohexyl; and aryl such as phenyl, tolyl, xylyl, benzyl, and2-phenylethyl. Each R¹⁵ is independently a hydrogen atom or analiphatically unsaturated hydrocarbon group exemplified by alkenyl suchas vinyl, allyl, butenyl, and hexenyl; and alkynyl such as ethynyl,propynyl, and butynyl. If one R¹⁵ is an aliphatically unsaturatedhydrocarbon group, then all R¹⁵ in the molecule may be the same ordifferent aliphatically unsaturated hydrocarbon group. If one R¹⁵ in amolecule is a hydrogen atom, then all R¹⁵ may be hydrogen atoms.

Component (IV) is exemplified by

-   i) dimethylvinylsiloxy-terminated polymethyl3,3,3-trifluoropropyl    siloxane,-   ii) dimethylvinylsiloxy-terminated    poly(methylhydrogensiloxane/methyl-6,6,6,5,5,4,4,3,3-nonafluorohexylsiloxane),-   iii) trimethylsiloxy-terminated    poly(methylhydrogensiloxane/methyl-6,6,6,5,5,4,4,3,3-nonafluorohexylsiloxane),    and-   iv) combinations thereof.

Alternatively, compoinent (IV) is exemplified by

-   i) dimethylvinylsiloxy-terminated polymethyl3,3,3-trifluoropropyl    siloxane,-   ii) dimethylvinylsiloxy-terminated    poly(methylhydrogensiloxane/methyl-6,6,6,5,5,4,4,3,3-nonafluorohexylsiloxane),-   iii) trimethylsiloxy-terminated    poly(methylhydrogensiloxane/methyl-6,6,6,5,5,4,4,3,3-nonafluorohexylsiloxane),-   iv) trimethylsiloxy-terminated    poly(methylhydrogensiloxane/methyl-3,3,3-trifluoropropylmethyl-6,6,6,5,5,4,4,3,3-nonafluorohexylsiloxane),-   v) trimethylsiloxy-terminated    poly(methylvinylsiloxane/methyl-6,6,6,5,5,4,4,3,3-nonafluorohexylsiloxane)    or-   vi) combinations thereof.

Component (IV) is added to the composition in an amount of 0.01 to 100parts by weight based on the weight of component (I). As the optimaloverall composition depends upon the specific properties desired such asviscosity, modulus, or cure speed, the optimal level of component (IV)may vary accordingly. Without wishing to be bound by theory, it isthought that the halogenated portion of component (IV) migrates to thesurface of the composition when cured. It is thought that sufficientchemical resistance for many applications can be obtained without addinga higher amount of component (IV), which would dramatically increase thecost of the composition. Without wishing to be bound by theory, it isthought that component (IV) also facilitates migration of component (V)to the surface of the composition and to other interfaces, furtherincreasing chemical resistance and improving adhesion. Component (IV)may be a combination of two or more fluoroorganosilicones that differ inat least one of the following properties: structure, average molecularweight, viscosity, siloxane units, and sequence.

Fluoroorganosilicones suitable for use as component (IV) are known inthe art. Fluoroorganosilicones may be prepared by those methodsdisclosed above for components (I) and (II), by varying appropriatestarting materials. One skilled in the art would be able to manufacturesuitable fluoroorganosilicones for component (IV) without undueexperimentation.

Component (V) Unsaturated Ester-Functional Compound

Component (V) is an unsaturated ester-functional compound, i.e., anorganic compound having at least one ester group per molecule and atleast one unsaturated group per molecule capable of undergoinghydrosilylation. Component (V) may comprise:

vi) a combination thereof.

In formula i), each R¹⁶ is independently a hydrogen atom, a monovalenthydrocarbon group of 1 to 4 carbon atoms, or CF₃. Examples of monovalenthydrocarbon groups for R¹⁶ include alkyl groups such as methyl, ethyl,propyl, and butyl. Each R¹⁷ is independently a hydrogen atom, amonovalent organic group, with the proviso that not all R¹⁷ are hydrogenatoms, or a metal ion. Examples of monovalent organic groups for R¹⁷include monovalent hydrocarbon groups, fluoroalkyl groups, epoxyfunctional groups, and polyether groups. Examples of monovalenthydrocarbon groups include, but are not limited to, alkyl such asmethyl, ethyl, propyl, pentyl, octyl, undecyl, dodecyl, and octadecyl;cycloalkyl such as cyclohexyl; alkenyl such as vinyl, allyl, butenyl,and hexenyl; alkynyl such as ethynyl, propynyl, and butynyl; and arylsuch as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl. Examples ofepoxy-functional groups for R¹⁷ include 3-glycidoxypropyl. Examples offluoroalkyl groups for R¹⁷ include but are not limited to—(CH₂)_(x)(CF₂)_(y)CF₃ where x has an average value of 0 to 20 and y hasan average value of 0 to 20, branched fluoroalkyl groups such asperfluoro t-butyl, and cyclic fluoroalkyl groups such asperfluorocyclohexyl, and fluoroaryl groups such as perfluorophenyl.Examples of polyether groups for R¹⁷ include, but are not limited to,—(CH₂CH₂O)_(z)CH₂CH₃, —(CH(CH₃)CH₂O)_(z)CH(CH₃)CH₃,—(CH2CH₂O)_(z)CH₂CH═CH₂, —(CH(CH₃)CH₂O)_(z)CH₂CH═CH₂,—(CH₂CH₂CH₂CH₂O)_(z)CH₂CH₃, —(CH₂CH₂CH₂CH₂O)_(z)CH═CH₂,—(CH₂CH₂O)_(z)CH₂CH₂OH, —(CH(CH₃)CH₂O)_(z)CH(CH₃)CH₂—OH,—(CH₂CH₂O)_(z)CH₂CH₂OCH3, and —(CH(CH₃)CH₂O)_(z)CH(CH₃)CH₂—OCH₃ where zhas an average value of 1 to 20, and cyclic ethers such astetrahydrofurfuryl and 2-(caprolactone)ethyl. Examples offluoropolyether groups for R¹⁷ include, but are not limited to,—(CF₂—CF₂—O)_(z)H, —(CF(CF₃)CF₂O)_(z)H, —(CF₂CF₂O)_(z)CF₃,—(CF(CF₃)CF₂O)_(z)CF₃, where z is as defined above,—(CH₂)_(i)(CF(CF₃))_(j)—(O—CF(CF₃)_(k)—F where i has an average value of0 to 10, j has an average value of 0 to 10 and k has an average value of1 to 20. Examples of metal ions for R¹⁷ include, but are not limited to,positive ions such as Zn, Al, Ca, Na, Mg and K.

In formula ii), each R¹⁸ is independently a hydrogen atom, a monovalenthydrocarbon group of 1 to 4 carbon atoms, or CF₃. Examples of monovalenthydrocarbon groups for R¹⁸ include alkyl such as methyl, ethyl, propyl,and butyl. Each R¹⁹ is independently a divalent organic group of 1 to 20carbon atoms. Examples of divalent organic groups for R¹⁹ include, butare not limited to, alkylene such as methylene, ethylene, propylene,pentylene, neo-pentylene, octylene, undecylene, and octadecylene;cycloalkylene such as cylcohexylene; alkenylene such as vinylene,allylene, butenylene, and hexenylene; alkynylene such as ethynylene,propynylene, and butynylene; arylene such as phenylene, tolylene,xylylene, benzylene, and 2-phenylethylene; ether diol derivatives suchas —(CH₂CH₂O)_(z)—CH₂CH₂— and —CH(CH₃)CH₂O)_(z)—CH(CH₃)CH₂ where z is asdefined above for R¹⁹; alkylene/arylene combinations such as4,4′-isopropylidene diphenyl (also known as Bisphenol “A”). Examples ofdivalent fluorinated organic groups for R¹⁹ include, but are not limitedto, —(CH₂)_(x)(CH(F))_(y)(CF₂)_(z)—, —(CF₂CF₂O)_(z)—,—(CF(CF₃)CF₂O)_(z)— where x, y, and z are as defined above,perfluorocyclohexyl-1,4-dimethyl, and 4,4′-hexafluoroisopropylidenediphenyl (derived from hexafluoro Bisphenol “A”). Each R²⁰ isindependently a hydrogen atom or a monovalent hydrocarbon group of 1 to20 carbon atoms. Examples of monovalent hydrocarbon groups for R²⁰include, but are not limited to, alkyl such as methyl, ethyl, propyl,pentyl, octyl, undecyl, and octadecyl; cycloalkyl such as cyclohexyl;alkenyl such as vinyl, allyl, butenyl, and hexenyl; alkynyl such asethynyl, propynyl, and butynyl; and aryl such as phenyl, tolyl, xylyl,benzyl, and 2-phenylethyl.

In formula iii), n has an average value of 0 to 3 and m=4-n.Alternatively, n may have a value of 0 to 2. Each R²¹ is independently ahydrogen atom, a monovalent hydrocarbon group of 1 to 20 carbon atoms, ahydroxyl group, or CF³. Examples of monovalent hydrocarbon groups forR²¹ include, but are not limited to, alkyl such as methyl, ethyl,propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl such ascyclohexyl; alkenyl such as vinyl, allyl, butenyl, and hexenyl; alkynylsuch as ethynyl, propynyl, and butynyl; and aryl such as phenyl, tolyl,xylyl, benzyl, and 2-phenylethyl.

Each R²² is independently a hydrogen atom, a monovalent hydrocarbongroup of 1 to 4 carbon atoms, or CF³. Examples of monovalent hydrocarbongroups for R²² include, but are not limited to, alkyl such as methyl,ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl such ascyclohexyl; alkenyl such as vinyl, allyl, butenyl, and hexenyl; alkynylsuch as ethynyl, propynyl, and butynyl; and aryl such as phenyl, tolyl,xylyl, benzyl, and 2-phenylethyl.

Each R²³ is independently a hydrogen atom or a monovalent hydrocarbongroup of 1 to 20 carbon atoms. Examples of monovalent hydrocarbon groupsfor R²³ include, but are not limited to, alkyl such as methyl, ethyl,propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl such ascyclohexyl; alkenyl such as vinyl, allyl, butenyl, and hexenyl; alkynylsuch as ethynyl, propynyl, and butynyl; and aryl such as phenyl, tolyl,xylyl, benzyl, and 2-phenylethyl.

In formula iv), each R²⁴ and each R²⁵ are independently a monovalentorganic group or a hydrogen atom with the proviso that at least one ofR²⁴ or R²⁵ is unsaturated. Examples of monovalent organic groups for R²⁴include monovalent hydrocarbon groups, fluoroalkyl groups, epoxyfunctional groups, and polyether groups, all exemplified by those listedfor R¹⁷.

Examples of monovalent organic groups for R²⁵ include monovalenthydrocarbon groups, fluoroalkyl groups, epoxy functional groups, andpolyether groups, all exemplified, but not limited, by those listed forR¹⁷. Additional examples of monovalent organic groups for R²⁵ includeoxygen-bridged monovalent organic groups such as—O—C(O)O—(CH₂)_(o)CH═CH₂ where o has an average value of 0 to 20 andcarbon-bridged carbonyl groups such as —CH₂—C(O)—CH₃.

In formula v), each R²⁶ is independently a monovalent organic group or ahydrogen atom, with the proviso that at least one R²⁶ is analiphatically unsaturated monovalent organic group or a hydrogen atom.Examples of monovalent organic groups for R²⁶ include monovalenthydrocarbon groups, fluoroalkyl groups, epoxy functional groups, andpolyether groups, all exemplified by those listed for R¹⁷.

Each R²⁷ is independently an oxygen atom or a divalent organic group.Examples of divalent organic groups for R²⁷ include divalent hydrocarbongroups, fluoroalkylene groups, epoxy functional groups, and polyethergroups, all exemplified, but not limited, by those listed for R¹⁹.

Component (V) is exemplified by 2-ethylhexylacrylate,2-ethylhexylmethacrylate, methylacrylate, methylmethacrylate,neopentylglycol diacrylate, neopentylglycoldimethacrylate, glycidylacrylate, glycidyl methacrylate, allyl acrylate, allyl methacrylatestrearyl acrylate, tetrahydrofurfuryl methacrylate, caprolactoneacrylate perfluorobutyl acrylate, perfluorobutyl methacrylate,tetrahydroperfluoroacrylate, phenoxyethyl acrylate, phenoxyethylmethacrylate, Bisphenol “A” acrylate, Bisphenol “A” dimethacrylate,ethoxylated Bisphenol “A” acrylate, ethoxylated Bisphenol “A”methacrylate, hexafluoro Bisphenol “A” diacrylate, hexafluoro Bisphenol“A” dimethacrylate, diethyleneglycol diacrylate, diethyleneglycoldimethacrylate, dipropyleneglycol diacrylate, dipropyleneglycoldimethacrylate, polyethyleneglycol diacrylate, polyethyleneglycoldimethacrylate, polypropyleneglycol diacrylate, polypropyleneglycoldimethacrylate, trimethylolpropanetriacrylate,trimethylolpropanetrimethacrylate, ethoxylatedtrimethylolpropanetriacrylate, ethoxylatedtrimethylolpropanetrimethacrylate), pentaerythritol triacrylate,pentaerythritol trimethacrylate), pentaerythritol tetraacrylate,pentaerythritol tetramethacrylate, methyl-3-butenoate, allyl methylcarbonate, diallyl pyrocarbonate, allyl acetoacetate, diallyl carbonate,diallyl phthalate, dimethyl itaconate, or a combination thereof.

Component (V) is added to the composition in an amount of 0.01 to 50weight parts based on the weight of the composition. Without wishing tobe bound by theory, it is thought that component (V) improves bothchemical resistance and the adhesive property of the cured product ofthe composition.

Unsaturated ester-functional compounds suitable for component (V) areknown in the art and commercially available from, for example, SartomerCompany and Aldrich Chemical Company. One skilled in the art would beable to obtain unsaturated ester-functional compounds without undueexperimentation.

Component (VI) Adhesion Promoter

Component (VI) is an adhesion promoter. Component (VI) is added to thecomposition in an amount of 0.01 to 50 weight parts based on the weightof the composition.

Component (VI) may comprise a transition metal chelate, an alkoxysilane,a combination of an alkoxysilane and a hydroxy-functionalpolyorganosiloxane, or a combination thereof.

Component (VI) can be an unsaturated or epoxy-functional compound.Suitable epoxy-functional compounds are known in the art andcommercially available, see for example, U.S. Pat. Nos. 4,087,585;5,194,649; 5,248,715; and 5,744,507 col. 4-5. Component (VI) maycomprise an unsaturated or epoxy-functional alkoxysilane. For example,the functional alkoxysilane can have the formula R²⁸_(μ)Si(OR²⁹)_((4-μ)), where μ is 1, 2, or 3, alternatively μ is 1.

Each R²⁸ is independently a monovalent organic group with the provisothat at least one R²⁸ is an unsaturated organic group or anepoxy-functional organic group. Epoxy-functional organic groups for R²⁸are exemplified by 3-glycidoxypropyl and (epoxycyclohexyl)ethyl.Unsaturated organic groups for R²⁸ are exemplified by3-methacryloyloxypropyl, 3-acryloyloxypropyl, and unsaturated monovalenthydrocarbon groups such as vinyl, allyl, hexenyl, undecylenyl.

Each R²⁹ is independently an unsubstituted, saturated hydrocarbon groupof at least 1 carbon atom. R²⁹ may have up to 4 carbon atoms,alternatively up to 2 carbon atoms. R²⁹ is exemplified by methyl, ethyl,propyl, and butyl.

Examples of suitable epoxy-functional alkoxysilanes include3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,(epoxycyclohexyl)ethyldimethoxysilane,(epoxycyclohexyl)ethyldiethoxysilane and combinations thereof. Examplesof suitable unsaturated alkoxysilanes include vinyltrimethoxysilane,allyltrimethoxysilane, allyltriethoxysilane, hexenyltrimethoxysilane,undecylenyltrimethoxysilane, 3-methacryloyloxypropyl trimethoxysilane,3-methacryloyloxypropyl triethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyl triethoxysilane, and combinationsthereof.

Component (VI) may comprise an epoxy-functional siloxane such as areaction product of a hydroxy-terminated polyorganosiloxane with anepoxy-functional alkoxysilane, as described above, or a physical blendof the hydroxy-terminated polyorganosiloxane with the epoxy-functionalalkoxysilane. Component (VI) may comprise a combination of anepoxy-functional alkoxysilane and an epoxy-functional siloxane. Forexample, component (VI) is exemplified by a mixture of3-glycidoxypropyltrimethoxysilane and a reaction product ofhydroxy-terminated methylvinylsiloxane with3-glycidoxypropyltrimethoxysilane, or a mixture of3-glycidoxypropyltrimethoxysilane and a hydroxy-terminatedmethylvinylsiloxane, or a mixture of 3-glycidoxypropyltrimethoxysilaneand a hydroxy-terminated methyvinyl/dimethylsiloxane copolymer. Whenused as a physical blend rather than as a reaction product, thesecomponents may be stored separately in multiple-part kits.

Suitable transition metal chelates include titanates, zirconates such aszirconium acetylacetonate, aluminum chelates such as aluminumacetylacetonate, and combinations thereof. Transition metal chelates andmethods for their preparation are known in the art, see for example,U.S. Pat. No. 5,248,715, EP 0 493 791 A1, and EP 0 497 349 B1.

Optional Components

An optional component may be added to the composition in addition tocomponents (I)-(VI). Suitable optional components include (VII) a voidreducing agent, (VIII) a pigment, (IX) a filler, (X) a cure modifier,(XI) a rheology modifier, (XII) a spacer, and combinations thereof.

Component (VII) Void Reducing Agent

Component (VII) is a void reducing agent. Component (VII) is added tothe composition in an amount sufficient to reduce voids. Suitable voidreducing agents are known in the art and commercially available, see forexample, EP 0 850 997 A2 and U.S. Pat. Nos. 4,273,902 and 5,684,060.Suitable void reducing agents can comprise zeolites, anhydrous aluminumsulfate, molecular sieves (preferably with a pore diameter of 10 Å orless), kieselguhr, silica gel, activated carbon, palladium compoundssuch as palladium metal, palladium metal supported on a substrateexemplified by carbon or alumina, and organopalladium compounds.

Component (VIII) Pigment

Component (VIII) is a pigment. The amount of component (VIII) added tothe composition depends on the type of pigment selected. Component(VIII) may be added to the composition in an amount of 0.001% to 30%based on the weight of the composition. Pigments are known in the artand commercially available. Suitable pigments include carbon blacks,such as LB-1011C carbon black from Williams, chromium oxide pigments,such as Harcros G-6099, titanium dioxides such as those available fromDuPont, and UV-active dyes such as(thiophenediyl)bis(t-butylbenzoxazole) which is commercially availableunder the name UVITEX OB from Ciba Specialty Chemicals.

Component (IX) Filler

Component (IX) is a filler. The amount of component (IX) added to thecomposition depends on the type of filler selected. Component (IX) maybe added to the composition in an amount of 0.1% to 90% based on theweight of the compositions. Suitable fillers include reinforcing fillerssuch silica, titania, and combinations thereof. Suitable reinforcingfillers are known in the art and commercially available, such as aground silica sold under the name MIN-U-SIL by U.S. Silica of BerkeleySprings, W. Va. or fumed silica sold under the name CAB-O-SIL by CabotCorporation of Massachusetts.

Conductive fillers (i.e., fillers that are thermally conductive,electrically conductive, or both) may also be used as component (IX).Suitable conductive fillers include metal particles, metal oxideparticles, and a combination thereof. Suitable thermally conductivefillers are exemplified by aluminum nitride; aluminum oxide; bariumtitanate; beryllium oxide; boron nitride; diamond; graphite; magnesiumoxide; metal particulate such as copper, gold, nickel, or silver;silicon carbide; tungsten carbide; zinc oxide, and a combinationthereof.

Conductive fillers are known in the art and commercially available, seefor example, U.S. Pat. No. 6,169,142 (col. 4, lines 7-33). For example,CB-A20S and Al-43-Me are aluminum oxide fillers of differing particlesizes commercially available from Showa-Denko, and AA-04, AA-2, and AA18are aluminum oxide fillers commercially available from Sumitomo ChemicalCompany. Silver filler is commercially available from MetalorTechnologies U.S.A. Corp. of Attleboro, Mass., U.S.A. Boron nitridefiller is commercially available from Advanced Ceramics Corporation,Cleveland, Ohio, U.S.A.

The shape of the conductive filler particles is not specificallyrestricted, however, rounded or spherical particles may preventviscosity increase to an undesirable level upon high loading of thethermally conductive filler in the composition.

A combination of thermally conductive fillers having differing particlesizes and different particle size distributions may be used. Forexample, it may be desirable to combine a first conductive filler havinga larger average particle size with a second conductive filler having asmaller average particle size in a proportion meeting the closestpacking theory distribution curve. This improves packing efficiency andmay reduce viscosity and enhance heat transfer.

The thermally conductive filler may optionally be surface treated with atreating agent. Treating agents and treating methods are known in theart, see for example, U.S. Pat. No. 6,169,142 (col. 4, line 42 to col.5, line 2). The thermally conductive filler may be treated with thetreating agent prior to combining the thermally conductive filler withthe other components of the composition, or the thermally conductivefiller may be treated in situ.

The treating agent can be an alkoxysilane having the formula: R³⁰_(p)Si(OR³¹)_((4-p)), where p is 1, 2, or 3; alternatively p is 3. R³⁰is a substituted or unsubstituted monovalent hydrocarbon group of atleast 1 carbon atom, alternatively at least 8 carbon atoms. R³⁰ has upto 50 carbon atoms, alternatively up to 30 carbon atoms, alternativelyup to 18 carbon atoms. R³⁰ is exemplified by alkyl groups such as hexyl,octyl, dodecyl, tetradecyl, hexadecyl, and octadecyl; and aromaticgroups such as benzyl, phenyl and phenylethyl. R³⁰ can be saturated orunsaturated, branched or unbranched, and unsubstituted. R³⁰ can besaturated, unbranched, and unsubstituted.

R³¹ is an unsubstituted, saturated hydrocarbon group of at least 1carbon atom. R³¹ may have up to 4 carbon atoms, alternatively up to 2carbon atoms. The treating agent is exemplified byhexyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane,dodecyltrimethyoxysilane, tetradecyltrimethoxysilane,phenyltrimethoxysilane, phenylethyltrimethoxysilane,octadecyltrimethoxysilane, octadecyltriethoxysilane, and a combinationthereof.

Alkoxy-functional oligosiloxanes can also be used as treatment agents.Alkoxy-functional oligosiloxanes and methods for their preparation areknown in the art, see for example, EP 1 101 167 A2. For example,suitable alkoxy-functional oligosiloxanes include those of the formula(R³²O)_(d)Si(OSiR³³ ₂R³⁴)_(4-d). In this formula, d is 1, 2, or 3,alternatively d is 3. Each R³² can be an alkyl group. Each R³³ can beindependently selected from saturated and unsaturated monovalenthydrocarbon groups of 1 to 10 carbon atoms. Each R³⁴ can be a saturatedor unsaturated monovalent hydrocarbon group having at least 11 carbonatoms.

Metal fillers can be treated with alkylthiols such as octadecylmercaptan and others, and fatty acids such as oleic acid, stearic acid,titanates, titanate coupling agents, zirconate coupling agents, and acombination thereof.

Treatment agents for alumina or passivated aluminum nitride couldinclude alkoxysilyl functional alkylmethyl polysiloxanes (e.g., partialhydrolysis condensate of R³⁵ _(b)R³⁶ _(c)Si(OR³⁷)_((4-b-c)) orcohydrolysis condensates or mixtures), similar materials where thehydrolyzable group would be silazane, acyloxy or oximo. In all of these,a group tethered to Si, such as R³⁵ in the formula above, is a longchain unsaturated monovalent hydrocarbon or monovalentaromatic-functional hydrocarbon. R³⁶ is a monovalent hydrocarbon group,and R³⁷ is a monovalent hydrocarbon group of 1 to 4 carbon atoms. In theformula above, b is 1, 2, or 3 and c is 0, 1, or 2, with the provisothat b +c is 1, 2, or 3. One skilled in the art could optimize aspecific treatment to aid dispersion of the filler without undueexperimentation.

Component (X) Cure Modifier

Component (X) is a cure modifier. Component (X) can be added to extendthe shelf life or working time, or both, of the composition of thisinvention. Component (X) can be added to raise the curing temperature ofthe composition. Suitable cure modifiers are known in the art and arecommercially available. Component (X) is exemplified by acetylenicalcohols such as methyl butynol, ethynyl cyclohexanol, dimethyl hexynol,and combinations thereof, cycloalkenylsiloxanes such asmethylvinylcyclosiloxanes exemplified by1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane,1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, andcombinations thereof; ene-yne compounds such as 3-methyl-3-penten-1-yne,3,5-dimethyl-3-hexen-1-yne; triazoles such as benzotriazole; phosphines;mercaptans; hydrazines; amines such as tetramethyl ethylenediamine,dialkyl fumarates, dialkenyl fumarates, dialkoxyalkyl fumarates,maleates, and combinations thereof.

Suitable cure modifiers are disclosed by, for example, U.S. Pat. Nos.3,445,420; 3,989,667; 4,584,361; and 5,036,117.

The amount of component (X) added to the composition will depend on theparticular cure modifier used, the nature and amount of component (III),and the composition of component (II). However, the amount of component(X) may be 0.001% to 10% based on the weight of the composition.

Component (XI) Rheology Modifier

Component (XI) is a rheology modifier. Rheology modifiers can be addedto change the thixotropic properties of the composition. Component (XI)is exemplified by flow control additives; reactive diluents;anti-settling agents; alpha-olefins; hydroxyl-terminatedsilicone-organic copolymers, including but not limited tohydroxyl-terminated polypropyleneoxidedimethylsiloxane copolymers; andcombinations thereof.

Component (XII) Spacer

Component (XII) is a spacer. Spacers can comprise organic particles,inorganic particles, or a combination thereof. Spacers can be thermallyconductive, electrically conductive, or both. Spacers can have aparticle size of 25 micrometers to 250 micrometers. Spacers can comprisemonodisperse beads. The amount of component (XII) depends on variousfactors including the distribution of particles, pressure to be appliedduring placement of the composition, temperature of placement, andothers. The composition can contain up to 15%, alternatively up to 5% ofcomponent (XII) added in addition to, or instead of, a portion ofcomponent (IX).

Other Optional Components

Other optional components may be added in addition to, or instead of,all or a portion of those described above, provided the optionalcomponent does not prevent the composition from curing to form asilicone product having improved adhesion and chemical resistance, asdescribed above. Examples of other optional components include, but arenot limited to, acid acceptors; anti-oxidants; stabilizers such asmagnesium oxide, calcium hydroxide, metal salt additives such as thosedisclosed in EP 0 950 685 A1, heat stabilizers, and ultra-violet (UV)stabilizers; flame retardants; silylating agents, such as4-(trimethylsilyloxy)-3-penten-2-one and N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide; desiccants, such as zeolites,anhydrous aluminum sulfate, molecular sieves (preferably with a porediameter of 10 Å or less), kieselguhr, silica gel, and activated carbon;and blowing agents, such as water, methanol, ethanol, iso-propylalcohol, benzyl alcohol, 1,4 butanediol, 1,5 pentanediol, 1,7heptanediol, and silanols.

Overall SiH: Vi Ratio

The components in the composition may be selected such that the molarratio of the total amount of silicon-bonded hydrogen atoms toaliphatically unsaturated groups in the composition (SiH_(tot)/Vi_(tot))is greater than 0.9, alternatively at least 1.0, and alternatively atleast 1.05. SiH_(tot)/Vi_(tot) may be up to 10.0, alternatively up to5.0, and alternatively up to 3.0. Without wishing to be bound by theory,it is thought that if SiH_(tot)/Vi_(tot) is too low, then thecomposition may not cure or may not adhere to some substrates. Withoutwishing to be bound by theory, it is thought that if SiH_(tot)/Vi_(tot)is too high, surface properties such as adhesion may be hindered andthere may be an increase in Bleed from within the formulation to othersurfaces.

Kits

The composition may be a one-part composition or a multiple-partcomposition such as a two-part composition. In a multiple-partcomposition, components (II) and (III) are stored in separate parts. Anyof components (I) and (IV)-(XI) can be added to either or both parts.One skilled in the art would know how to select components for each partwithout undue experimentation.

When a multiple part composition is prepared, it may be marketed as akit. The kit may further comprise information or instructions or both ashow to use the kit, how to combine the parts, or how to cure theresulting combination, or combinations thereof. For example, a kitcomprising Part A and Part B can be prepared as follows.

Part A comprises:

-   -   (I) a polyorganosiloxane having at least two        terminally-unsaturated organic groups per molecule,    -   (III) a hydrosilylation catalyst,    -   optionally (IV) a haloorganosilicone having at least one        functional group reactive with component (I),    -   optionally (V) an unsaturated ester-functional compound,    -   optionally (VI) an adhesion promoter,    -   optionally (VII) a void reducing agent,    -   optionally (VIII) a pigment,    -   optionally (IX) a filler,    -   optionally (X) an cure modifier,    -   optionally (XI) a rheology modifier, and    -   optionally (XII) a spacer.

Part B comprises:

-   -   optionally (I) a polyorganosiloxane having at least two        terminally-unsaturated organic groups per molecule,    -   (II) an organohydrogenpolysiloxane having at least two        silicon-bonded hydrogen atoms per molecule,    -   optionally (IV) a haloorganosilicone having at least one        functional group reactive with component (I), component (II), or        both,    -   optionally (V) an unsaturated ester-functional compound,    -   optionally (VI) an adhesion promoter,    -   optionally (VII) a void reducing agent,    -   optionally (VIII) a pigment,    -   optionally (IX) a filler,    -   optionally (X) an cure modifier,    -   optionally (XI) a rheology modifier, and    -   optionally (XII) a spacer.

In the kit, at least one of Part A and Part B contains component (IV),and at least one of Part A and Part B contains component (V).

Part A and Part B can be mixed together in a ratio of Part A: Part B(A:B) of 0.05:1 to 20:1, alternatively 0.1:1 to 10:1, alternatively 1:1to 5:1.

Method of Making the Composition

The compositions described above can be prepared by mixing thecomponents by any convenient means. For example, the composition can beprepared by mixing all components at ambient temperature. When component(X) is present, component (X) may be added before component (III).

The mixer used is not specifically restricted and will be determined bythe viscosity of the components and the composition. Suitable mixersinclude but are not limited to paddle type mixers, kneader type mixers,non-intrusive mixers such as those reliant on centrifugal motion, andtwo- and three-roll rubber mills. One skilled in the art would be ableto prepare the composition without undue experimentation by the methodsdisclosed above and in the examples set forth below.

Method of Use

The composition of this invention is useful for a range of applicationswhere modified surface or interface properties, or both, are desired.For example, the compositions described above cure to form a part thatcan be used as an adhesive; protective coating for electronic circuitry,planar surfaces, fibers or small particles; or gasketing materials.Exposed surfaces of the fully cured or partially cured products of thiscomposition may also be useful as substrates for bonding by anotheradhesive or for secondary bonding to another substrate (as exemplifiedby a dry film adhesive).

The composition of this invention cures to form a product that can beused as an adhesive. The composition can be cured at ambient or elevatedtemperature. The composition may be applied to a substrate before orduring curing. Exposed surfaces of the fully cured or partially curedproducts of this invention may also be useful as a substrate for bondingby another adhesive or for secondary bonding to another substrate (asexemplified by a dry film adhesive). The adhesives may be used, forexample, as products such as die attach adhesives, as lid seals, gelsand encapsulants.

Cured products prepared using the compositions of this invention canvary in properties from rigid resins to elastomers to gels, dependingupon the types and concentrations of components (I) and (II) and anyoptional components that are added to the composition. Cured productsprepared using the compositions are useful in a variety of end-useapplications, for example, as coatings or as molded or extrudedarticles. The compositions can be applied to substrates by spraying,dipping, pouring, screen printing, extrusion or by the use of a brush,roller or coating bar. The selection of a particular application methodwill be determined at least in part by the viscosity of the curablecomposition.

Suitable substrates to which the composition, or cured product thereof,may be applied and which are useful in electronics applications includeepoxies, polycarbonates, poly(butylene terephthalate) resins, polyamideresins and blends thereof, such as blends of polyamide resins withsyndiotactic polystyrene such as those commercially available from theDow Chemical Company, of Midland, Mich., U.S.A.,acrylonitrile-butadiene-styrenes, styrene-modified poly(phenyleneoxides), poly(phenylene sulfides), vinyl esters, polyphthalamides,polyimides, silicon, aluminum, stainless steel alloys, titanium, copper,nickel, silver, gold, and combinations thereof.

The composition of this invention can be used, for adhering twosurfaces, such as in lid seal applications. For example, the compositioncan be used for gluing a plastic lid onto a plastic housing forelectronic circuitry in an assembly process by a method comprising:

-   -   (1) applying the composition described above onto the plastic        housing,    -   (2) placing the lid over the housing such that the edges of the        lid are in contact with the composition, and    -   (3) curing the assembly to form a sealed housing.

Alternatively, the composition can be used, for example, to coat anelectronic circuit board, by method comprising:

-   -   (1) applying the composition described above over the electronic        circuit board, and    -   (2) curing the composition to produce a sealed circuit board.

Alternatively, the composition can be used, for example, for die attachapplications, in a method comprising:

-   -   (1) applying the composition described above on an electronic        substrate,    -   (2) attaching a semiconductor die to the composition,    -   (3) curing the composition to produce a bonded composite.

The method may further comprise one or more optional steps such as (4)repeating steps (1) to (3) to attach one or more additionalsemiconductor dice to the semiconductor die, (5) wire bonding thesemiconductor die or semiconductor dice, (6) cleaning, for example byexposure to plasma, (7) overmolding the semiconductor die orsemiconductor dice with a molding compound, and (8) attaching solderballs to form a finished package. In step (1), the electronic substratemay be, for example, a circuit board, a TAB tape, or other substrateknown in the art, or the electronic substrate may be a semiconductordie.

FIG. 3 shows an example of a package 300 prepared according to thismethod. The package 300 includes a semiconductor die 301 bonded to asubstrate 302 shown as a polyimide TAB tape flexible circuit through adie attach adhesive 303 prepared from the composition of this invention.The semiconductor die 301 is electrically connected to the substrate 302through lead bonds 304. The shapes of the lead bonds 304 are dependenton the height of the semiconductor die 301 from the substrate 302.Encapsulant 305 is used to protect the lead bonds 304. FIG. 4 also showsthe solder balls 306, which provide the connection mechanism to thesubstrate (not shown) on which the package 300 will be mounted.

The composition of this invention may be printed or dispensed on thesubstrate 302. The semiconductor die 301 may then be placed withpressure and heat onto the composition to prepare the die attachadhesive 303.

FIG. 4 shows an example of a package 400 prepared according to thismethod. The package includes a first semiconductor die 401 stacked ontop of a second semiconductor die 402 and attached through a first dieattach adhesive 403. The second semiconductor die 402 is mounted to asubstrate 404 shown in FIG. 4 as a circuit board through a second dieattach adhesive 405. The first die attach adhesive 403 and the seconddie attach adhesive 405 are prepared by curing the composition of thisinvention. The first die attach adhesive 403 and the second die attachadhesive 405 may be the same or different.

The package 400 may be assembled, for example, by applying a compositionaccording to this invention to the substrate 404. The secondsemiconductor die 402 may be heated and placed onto the composition withenough pressure to spread the composition uniformly under the secondsemiconductor die 402. The heat of the die may partially or fully curethe composition to form the second die attach adhesive 405. Acomposition according to this invention may then be applied to the topof the second semiconductor die 402 and the first semiconductor die 401may be applied hot to the composition with sufficient pressure, asdescribed above. The composition partially or fully cures to form thefirst die attach adhesive 403.

The first semiconductor die 401 is electrically connected to thesubstrate through bonding wires 406 and the second semiconductor die 402is electrically connected to the substrate through bonding wires 407. Anovermolding 408 may then be applied to protect the semiconductor dice401, 402 and the bonding wires 406, 407. Solder balls 409 may then beadded to the substrate 404.

EXAMPLES

These examples are intended to illustrate the invention to one skilledin the art and should not be interpreted as limiting the scope of theinvention set forth in the claims. The following components are used inthese examples.

Blend 1 is a mixture of (i) 27 parts of an organopolysiloxane resinconsisting essentially of CH₂═CH(CH₃)₂SiO_(1/2) units, (CH₃)₃SiO_(1/2)units, and SiO_(4/2) units, wherein the mole ratio ofCH₂═CH(CH₃)₂SiO_(1/2) units and (CH₃)₃SiO_(1/2) units combined toSiO_(4/2) units is 0.7, and the resin has weight-average molecularweight of 22,000, a polydispersity of 5, and contains 1.8% by weight(5.5 mole %) of vinyl groups, (ii) 71 parts of adimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosityof 55 Pa.s at 25° C., (iii) 0.1 part ethyl benzene, (iv) 0.4 partxylene, (v) 0.5 part tetra(trimethylsiloxy)silane, and (vi) 0.7 partdimethyl cyclosiloxanes.

PDMS 1 is dimethylvinyl siloxy-terminated linear polydimethylsiloxanehaving a viscosity of 450 cP at 25° C.

Catalyst 1 is a mixture of 1% of a platinum(IV) complex of1,1-diethenyl-1,1,3,3-tetramethyldisiloxane, 92% ofdimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosityof 0.45 Pa.s at 25° C., and 7% of tetramethyldivinyldisiloxane.

Adhesion Promoter 1 is a mixture of 46%3-glycidoxypropyltrimethoxysilane, 40% hydroxy-terminatedmethylvinylsiloxane, 7% cyclic methylvinylsiloxane, 6% a reactionproduct of hydroxy terminated methylvinyl siloxane, with3-glycidoxypropyltrimethoxysilane, and 1% methanol. The mixture has aviscosity of 15 cSt at 25° C.

Void Reducing Agent is palladium on carbon.

Pigment is carbon black from Williams.

Quartz is a ground silica sold under the name MIN-U-SIL 5 by U.S. Silica(Berkeley Springs, W. Va.). The silica has a topsize of 5 μm (98% <5μm), a median particle size of 1.6 μm, a tapped density of 41, anuntapped density of 31, and a specific gravity of 2.65.

Organohydrogenpolysiloxane 1 is a trimethylsiloxy-terminatedpoly(dimethylsiloxane/methylhydrogensiloxane) having an average of 3dimethylsiloxane units and 5 methylhydrogensiloxane units per moleculeand containing 0.8% of silicon-bonded hydrogen atoms.

Unsaturated ester-functional compound 1 is neopentylglycol diacrylate.

Unsaturated ester-functional compound 2 is neopentylglycoldimethacrylate.

Fluoroorganosilicone 1 is dimethylvinylsiloxy-terminated methyl3,3,3-trifluoropropyl siloxane having 0.5 to 2% vinyl groups and aviscosity of 310 to 2000 cSt at 25° C.

Fluoroorganosilicone 2 is trimethylsiloxy-terminatedpoly(methylhydrogensiloxane/methyl-6,6,6,5,5,4,4,3,3-nonafluorohexylsiloxane)having an average of 28 methylhydrogensiloxane units and 12methyl-6,6,6,5,5,4,4,3,3-nonafluorohexyl siloxane units per molecule.

Organohydrogenpolysiloxane 2 is methylhydrogen siloxane having aviscosity of 20 to 40 cSt at 25° C. and 1.4 to 1.75% hydrogen by weight.

Cure Modifier 1 is 3,5-dimethyl-1-hexyn-3-ol.

Reinforcing Silica is hexamethyldisilazane-treated silica having a BETsurface area of between 200 and 250 meters squared per gram (m²/g), pHof 4.5 to 6.5, and moisture content not exceeding 0.6% measuredgravimetrically at 105° C. This material is sold under the name ofCab-O-Sil TS-530 by Cabot Corporation.

Rheology modifier is a trimethylsiloxy-terminated dimethyl,methyl(propyl(poly(propyleneoxide)hydroxy)) siloxane copolymer, having aviscosity of 140 to 190 centiStokes (cSt). Rheology modifier is soldunder the name of 1248 Fluid by Dow Corning Corporation.

The following substrates are used in these examples.

FR-4 is the epoxy side of a copper-clad FR-4 (glass-reinforced epoxy)laminate having a thickness of 0.152 centimeters (cm), which isavailable from Laird Plastics (West Palm Beach, Fla.).

PC is a Bisphenol A polycarbonate sheet having a thickness of 0.635 cm,which is sold under the name HYZOD M by Exotic Automation & Supply(Farmington Hills, Mich.).

PBT is a poly(butylene terephthalate) resin sheet having a thickness of0.635 cm, which is sold under the name HYDEX 4101 (white) by BoedekerPlastics, Inc. (Shiner, Tex.).

GF-PBT is a glass-reinforced poly(butylene terephthalate) resin sheethaving a thickness of 0.318 cm, which is sold under the name Celanex3300 D (black) by Ticona (Summit, N.J.).

N66 is an extruded nylon type 6/6 polyamide resin sheet having athickness of 0.635 cm, which is available from Boedeker Plastics, Inc.(Shiner, Tex.).

ABS is an acrylonitrile-butadiene-styrene sheet having a thickness of0.635 cm, which is available from Boedeker Plastics, Inc. (Shiner,Tex.).

PPO is a styrene-modified poly(phenylene oxide) sheet having a thicknessof 0.635 cm, which is sold under the name NORYL EN-265 (black) byBoedeker Plastics, Inc. (Shiner, Tex.).

PPS is a poly(phenylene sulfide) sheet having a thickness of 0.318 cm,which is sold under the trademark TECHTRON PPS (natural) by BoedekerPlastics, Inc. (Shiner, Tex.).

Al is a die-cast aluminum having a thickness of 0.163 cm.

SS is a 304 stainless steel alloy (Type SS-34) panel having a thicknessof 0.160 cm, which is available from Q-Panel Lab Products (Cleveland,Ohio).

Cu is the copper side of a copper-clad FR-4 (glass-reinforced epoxy)laminate having a thickness of 0.152 cm, which is available from LairdPlastics (West Palm Beach, Fla.).

PA-sPS1 is a thermoplastic which comprises 70% of a blend and 30% glassfiller. The blend comprises 70% Nylon 66 and 30% syndiotacticpolystyrene. PA-sPS1 is commercially available from The Dow ChemicalCompany (Midland, Mich.).

PA-sPS2 is a thermoplastic which comprises 90% of a blend and 10% glassfiller. The blend comprises 70% Nylon 66 and 30% syndiotacticpolystyrene. PA-sPS2 is commercially available from The Dow ChemicalCompany (Midland, Mich.).

PA-sPS3 is a thermoplastic which comprises 70% of a blend and 30% glassfiller. The blend comprises 50% Nylon 66 and 50% syndiotacticpolystyrene. PA-sPS3 is commercially available from The Dow ChemicalCompany (Midland, Mich.).

Vinyl ester is a compression molded glass-filled vinylester thermosetsubstrate available from The Dow Chemical Company under the trade nameof Premi-Glas® 1285VE.

PPA is a 30% glass-filled polyphthalamide. The polyphthalamide resin isavailable from Solvay Advanced Polymers under the trade name of Amodel®.

Reference Example 1 Cleaning of Substrates

Plastic substrates, except Nylon, are first cleaned in an ultrasonicbath containing a dilute soap solution to remove machine oils and otherhydrocarbon residues, and are rinsed in clean water. Immediately beforeuse, each plastic substrate is repeatedly cleaned by drawing a Kimwipedisposable wiper saturated with isopropyl alcohol over the test surface.In the final cleaning step, isopropyl alcohol is applied to the testsurface using a TECHNICLOTH TX604 clean room wiper (The Texwipe Company,Upper Saddle River, N.J.). The test surface of each Nylon substrate issprayed with isopropyl alcohol, is wiped with a Kimwipe, is sprayed withacetone, and is wiped with a TECHNICLOTH TX604 clean room wiper. Metalsubstrates are cleaned in a similar manner using heptane followed byisopropyl alcohol. All substrates are allowed to air-dry for at leasttwenty minutes before application of a silicone composition.

Reference Example 2 Preparation of Specimens for Scrape Adhesion Testingand Measurement of Scrape Adhesion

The freshly prepared adhesive composition is drawn over the surface of acleaned substrate with a doctor blade to achieve a film thickness of0.025 in. (0.0635 cm). The coated substrate is then heated in a forcedair convection oven at a temperature of 150° C. for 30 minutes and thenis allowed to cool to room temperature. The substrate is scored with arazor blade to form two parallel lines separated by 0.25 in. (0.635 cm),penetrating through the adhesive layer and into the substrate.

A stainless steel microspatula (Fisherbrand 21-401-5) having roundedends is brought into contact with the adhesive surface between the twoparallel score lines, described above, at an angle of approximately 30°from the surface. A manual force is exerted on the spatula along thetrack between the score lines in an attempt to scrape the adhesive fromthe surface of the substrate. The failure mode is reported as adhesive,cohesive, or a combination thereof. Adhesive failure denotes cleandebonding (release) of the silicone product from the substrate. Cohesivefailure denotes fracture (splitting) of the silicone product itself andadherence of residue to the substrate.

Reference Example 3 Preparation of Lap Shear Specimens and Measurementof Adhesion by Single Lap Shear Testing

Cleaned substrates are placed in a machined aluminum support jigdesigned to support two 3-inch long substrate panels with an overlaparea of 1 square inch, or 0.5 square inches, and a bondline thickness of0.030 inches. The adhesive composition to be tested is applied with amicrospatula, spreading out carefully to not incorporate air into thesample. A second cleaned substrate is placed over the adhesive and iscompressed to form the appropriate thickness by lightly screwing downthe upper restraining bar. Samples are transferred to a convection ovenpre-set to 150° C. and are allowed to cure for 60 min. Following removalfrom the oven and cooling to room temperature, the specimens are removedfrom the jigs, and all excess adhesive is trimmed away completely fromthe edges of the lap region with a razor blade. After 24 hours, thesamples are loaded into a MTS Sintech 5/G tensile tester equipped with a5000 pound-force transducer and tested at a crosshead speed of 2 inchesper minute (in/min) (0.085 cm/second) (under ambient conditions. Medianvalues of maximum stress from at least three replicates of eachsubstrate/composition combination are reported along with mode offailure rated by estimated percentage of total bond area exhibitingcohesive failure (CF). In cases where fracture occurs through thesilicone product but very close to one of the substrate surfaces toleave only a thin film of residue, this effect is additionally noted as“thin film” failure.

Reference Example 4 Preparation of Specimens for Chemical resistanceTesting and Measurement of Chemical Resistance

The adhesive composition is coated on substrates and cured as describedin Reference Example 3. The resulting samples are immersed continuouslyin 10W30 motor oil at 150° C. for 500 hours without changing the oil.Shear strength of the adhesive is measured before and after oilimmersion.

Reference Example 5 Determination of Interface Compositions by SurfaceAnalysis

Samples are cast to a standard thickness of 0.025 inch (in) (0.0635centimeter) the manner described in Reference Example 2, except that thesamples are cured for 30 minutes in a convection oven pre-heated to 70°C., on polycarbonate substrates 101 cleaned as described in ReferenceExample 1 and as shown in the schematic shown in FIG. 1. Cured samples102 are examined spectroscopically in multiple spots along three planesof interest: the free surface 103, bulk 104, and substrate interface105, as represented. To avoid atmospheric contamination, samples areloosely wrapped in clean, heavy gauge aluminum foil prior to and aftertesting. The substrate interface is exposed by carefully peeling awaythe cured film, if possible. In cases of very strong adhesion, thesamples are either cryogenically fractured or carefully cut away toexpose the interface. In the latter case, spectra from both sides of theinterface are compared to ensure the separation did not occurcohesively. Bulk spectra are obtained from fresh areas exposed byslicing away a thin layer from the surface with a clean microtome blade.No attempt is made to control the thickness of this slice preciselybecause this technique gave access to areas that were well beyond the1-2 micrometer (μm) depths where gradients are strongest. This isconfirmed by good reproducibility among bulk spectra from random slices.

Reference Example 6 Surface Analysis by X-Ray Photoelectron Spectroscopy

X-ray photoelectron spectroscopy (XPS) analyses are obtained using aKratos AXIS 165 instrument with a monochromatic x-ray source at 280W.Charge compensation is employed. This method gives an analysis spot sizeof 0.7 millimeters (mm)×1.4 mm. Three short strips are cut from eachsample to provide substrate (105) and air (103) interfaces and a ‘bulk’(104) composition (numbers used to describe the various surfaces areshown in FIG. 1). The strips are 3-5 mm wide and 10-15 mm long. Thesamples are mounted to a long sample stage using metal clips. Twopositions (106, 107) on each strip are analyzed by XPS. A low resolutionsurvey spectrum and high resolution spectra of O, C and Si are obtainedat each position analyzed.

Reference Example 7 Surface Analysis by ATR-IR Test Method

A Spectratech attenuated total reflectance infrared spectroscopy(ATR-IR) microscope is used to compare concentration at various depthsof cured silicone films. This apparatus is equipped with an ATRobjective lens consisting of a hemispherical Zn—Se crystal providing anangle of incidence of 38.68°. This geometry probes a depth of 2±0.5 μmin the IR regions of interest. The sample is raised gently until astandard contact pressure reading is reached on a stage-mounted pressuresensor to ensure similar levels of contact for all spectra. Between eachnew spectrum, the crystal is cleaned by gently wiping with a Kimwipemoistened with analytical grade heptane and allowed to dry completely.In all ATR-IR experiments, sample chambers are thoroughly purged withdry nitrogen gas before obtaining background spectra. Each spectrum isgenerated with 256 scans. Absorption peak height analysis is performedwith standardized baseline points using Omnic™ software.

Three replicate spectra (depicted schematically as spots 106, 107, 108in FIG. 1) are obtained at each of the three surfaces (spots 103, 104,105). For each spectrum (such as any of the three spectra shown in FIG.2), the normalized peak heights for both the carbonyl (—C═O) stretch at1740 cm⁻¹ and silicon hydride (—Si—H) at 2160 cm⁻¹ are calculated bydividing by the peak height of the silicon-methyl (—Si-Me) band at 1446cm⁻¹. The normalized peak heights are then averaged over the threereplicates. Comparison of the relative level of interface enrichmentwith respect to the bulk is made by dividing the average normalized peakratio for the air and substrate interfaces (103 and 105, respectively)by the corresponding value in the bulk (104).

Example 1 Two-Part Adhesive Composition

A two-part adhesive composition is prepared. Part A is prepared bymixing 93.3 parts Blend 1, 0.7 part Catalyst 1, 4.8 parts AdhesionPromoter 1, 0.6 part Void Reducing Agent, and 0.6 part Pigment. Part Bis prepared by mixing 36.1 parts of Blend 1, 43.4 parts of Quartz, 5.1parts Organohydrogenpolysiloxane 1, 3.1 parts Unsaturatedester-functional compound 1, 4.9 parts Fluoroorganosilicone 1, 0.6 partOrganohydrogenpolysiloxane 2, and 6.8 parts Fluoroorganosilicone 2.

Parts A and B are mixed in a 2.6:1 (A:B) ratio using a Hauschild mixerfor two 12 second mixing cycles. The resulting adhesive composition iscured and tested according to the method of Reference Example 2. Theresults are in Table 1. The resulting adhesive composition is cured andtested according to the method of Reference Example 4. The results arein Table 2.

Comparative Example 1

A two-part adhesive composition is prepared. Part A is prepared bymixing 94.0 parts Blend 1, 0.6 part Catalyst 1, 4.8 parts AdhesionPromoter 1, and 0.6 part Pigment. Part B is prepared by mixing 47.7parts of Blend 1, 47.1 parts of Quartz, 4.3 partsOrganohydrogenpolysiloxane 1, and 0.83 part Organohydrogenpolysiloxane2.

Parts A and B are mixed in a 2.0:1 (A:B) ratio using a Hauschild mixerfor two 12 second mixing cycles. The resulting adhesive composition iscured and tested according to the method of Reference Example 2. Theresults are in Table 1. The resulting adhesive composition is cured andtested according to the method of Reference Example 4. The results arein Table 2.

TABLE 1 Failure of Adhesive of Failure of Adhesive of Substrate Example1 Comparative Example 1 PA-sPS2 100% cohesive Adhesive Al 100% cohesive100% cohesive Vinyl 100% cohesive 100% cohesive ester FR-4 100% cohesive100% cohesive PC 100% cohesive Adhesive N66 100% cohesive AdhesiveGF-PBT 100% cohesive 100% Cohesive PBT Partially cohesive Adhesive PPO100% cohesive 100% cohesive PPS 100% cohesive Partially cohesive PPA100% cohesive 100% cohesive Cu 100% cohesive 100% cohesive SS 100%cohesive 100% cohesive ABS 100% cohesive Partially cohesive

TABLE 2 Comparative Comparative Example 1 Shear Example 1 Shear Example1 Shear Example 1 Shear Strength & Strength & Strength &Failure Strength& Failure Mode Failure Mode Mode before Failure Mode before Immersionafter Immersion Immersion after Immersion Substrate kPa (% CF) kPa (%CF) kPa (% CF) kPa (% CF) PA-sPS1 3206 ± 310 Not measured 1593 ± 103(0%) Not measured (100%) PA-sPS2 3096 ± 186 Not measured 2158 ± 69 (60%)Not measured (100%) PA-sPS3 2765 ± 138 Not measured 1600 ± 110 (0%) Notmeasured (100%) Vinyl 3330 ± 138 1813 ± 97 3006 ± 414 (100%) 1248 ± 193Ester (100%) (100%*) (100%*) *Denotes that up to 20% of the failuresurface showed a thin film residue of silicone, with the remainder ofthe area showing fracture through the center of the silicone product.

Example 1 and Comparative Example 1 show that the combination of mixtureof organohydrogenpolysiloxanes, the Fluoroorganosilicone additive, andthe unsaturated ester-functional compound provide improved adhesion andchemical resistance.

Example 2 Adhesive Composition

A one-part adhesive composition is prepared by mixing 52.76 parts Blend1, 29.97 parts Quartz, 0.19 part Catalyst 1, 1.32 parts AdhesionPromoter 1, 0.18 part Void Reducing Agent, 0.18 part Pigment, 4.17 partsOrganohydrogenpolysiloxane 1, 2.20 parts Unsaturated ester functionalcompound 1, 3.52 parts Fluoroorganosilicone 1, 0.45 partOrganohydrogenpolysiloxane 2, 4.90 parts Fluoroorganosilicone 2, and0.18 part Cure Modifier 2. Lap shear strength is tested according to themethod of Reference Example 3. The results are in Table 3.SiH_(B)/Vi_(A) is 3.7 and SiH_(tot)/Vi_(tot) is 1.55.

Example 3 Composition of Example 2 with Optional Components

A one-part adhesive composition is prepared by mixing 50.59 parts Blend1, 28.47 parts Quartz, 0.19 part Catalyst 1, 1.33 parts AdhesionPromoter 1, 0.18 part Void Reducing Agent, 0.18 part Pigment, 4.02 partsOrganohydrogenpolysiloxane 1, 2.21 parts Unsaturated ester functionalcompound 1, 3.54 parts Fluoroorganosilicone 1, 0.45 partOrganohydrogenpolysiloxane 2, 4.92 parts Fluoroorganosilicone 2, 0.18part Cure Modifier 2, 3.54 parts Reinforcing Silica, and 0.22 partRheology modifier.

Lap shear strength is tested according to the method of ReferenceExample 3. The results are in Table 3. Example 3 shows that addition ofrheology modifiers and reinforcing fillers is not detrimental to theeffectiveness of this invention.

Comparative Example 2 Adhesive Composition withoutFluoroorganosilicones, Unsaturated Ester and Organohydropenpolysiloxane2

A one-part adhesive composition is prepared by mixing 62.26 parts Blend1, 31.64 parts Quartz, 0.19 part Catalyst 1, 1.36 parts AdhesionPromoter 1, 0.20 part Void Reducing Agent, 0.20 part Pigment, 3.96 partsOrganohydrogenpolysiloxane 1, and 0.18 part Cure Modifier 2. Lap shearstrength is tested according to the method of Reference Example 3. Theresults are in Table 3.

Comparative Example 3 Adhesive Composition without Fluoroorganosiliconesand Unsaturated Ester Compound, but with Organohydrogenpolysiloxane 2

A one-part adhesive composition is prepared by mixing 62.43 parts Blend1, 31.73 parts Quartz, 0.19 part Catalyst 1, 1.36 parts AdhesionPromoter 1, 0.20 part Void Reducing Agent, 0.20 part Pigment, 3.34 partsOrganohydrogenpolysiloxane 1, 0.36 part Organohydrogenpolysiloxane 2,and 0.18 part Cure Modifier 2. Lap shear strength is tested according tothe method of Reference Example 3. The results are in Table 3.

TABLE 3 Example 3 Example 2 Lap Shear Comparative Comparative Lap ShearStrength Example 2 Example 3 Strength &Mode &Mode of Lap Shear StrengthLap Shear Strength of Failure Failure &Mode of Failure &Mode of FailureSubstrate kPa (% CF) kPa (% CF) kPa (% CF) kPa (% CF) PA-sPS1 2275 ± 2762834 ± 117  689 ± 90 (0%) 1014 ± 83 (0%) (100%) (90%) PA-sPS2 2455 ± 3172717 ± 372 1813 ± 338 (100%) 2675 ± 296 (100%) (100%) (100%) PA-sPS32068 ± 124 2317 ± 90 1041 ± 83 (0%) 1069 ± 110 (0%) (100%, thin film)(100%, thin film)

Example 2 and Comparative Example 2 illustrate that the combination ofmixture of organohydrogenpolysiloxanes, the Fluoroorganosiliconeadditives, and the unsaturated ester functional compound provideimproved adhesion to polyamide-syndiotactic blends. Comparative Example3 shows that a similar improvement in adhesion is not achieved by use ofa organohydrogenpolysiloxane mixture alone in this composition.

Comparative Example 4 Composition of Example 2 without UnsaturatedEster-Functional Compound

A one-part adhesive composition is prepared by mixing 57.53 parts Blend1, 32.67 parts Quartz, 0.21 part Catalyst 1, 1.32 parts AdhesionPromoter 1, 0.19 part Void Reducing Agent, 0.19 part Pigment, 3.08 partsOrganohydrogenpolysiloxane 1, 3.84 parts Fluoroorganosilicone 1, 0.45part Organohydrogenpolysiloxane 2, 0.32 part Fluoroorganosilicone 2, and0.19 part Cure Modifier 2. Lap shear strength is tested according to themethod of Reference Example 3. The results are in Table 4.

Comparative Example 5 Composition of Example 2 without UnsaturatedEster-Functional Compound and with Equivalent Weight ofFluoroorganosilicone

A one-part adhesive composition is prepared by mixing 56.42 parts Blend1, 32.05 parts Quartz, 0.21 part Catalyst 1, 1.32 parts AdhesionPromoter 1, 0.19 part Void Reducing Agent, 0.19 part Pigment, 0.57 partOrganohydrogenpolysiloxane 1, 3.53 parts Fluoroorganosilicone 1, 0.45part Organohydrogenpolysiloxane 2, 4.89 parts Fluoroorganosilicone 2,and 0.19 part Cure Modifier 1. Lap shear strength is tested according tothe method of Reference Example 3. The results are in Table 4.

Comparative Example 6 Composition Example 2 withoutFluoroorganosilicones

A one-part adhesive composition is prepared by mixing 56.43 parts Blend1, 32.05 parts Quartz, 0.21 part Catalyst 1, 1.32 parts AdhesionPromoter 1, 0.19 part Void Reducing Agent, 0.19 part Pigment, 6.77 partsOrganohydrogenpolysiloxane 1, 2.21 parts Unsaturated ester functionalcompound 1, 0.45 part Organohydrogenpolysiloxane 2, and 0.19 part CureModifier 2. Lap shear strength is tested according to the method ofReference Example 3. The results are in Table 4.

TABLE 4 Comparative Example 4 Comparative Comparative Lap Shear Mode ofExample 5 Mode of Example 6 Mode of Strength Failure Lap Shear FailureLap Shear Failure Substrate (kPa) (% CF) Strength (kPa) (% CF) Strength(kPa) (% CF) PA-sPS1 1800 ± 200 80 827 ± 131  50 2779 ± 138 100 PA-sPS31648 ± 28  10 687 ± 7  100 2034 ± 152  70 (thin (thin film) film)

Example 4 Composition for Surface Analysis

A two-part model base formulation is prepared by mixing 35.1 parts ofPDMS 1, 64.7 parts of Quartz, and 0.39 part of Catalyst 1 as Part A.Part B is prepared by mixing 37.8 pats of PDMS 1, 59.9 parts Quartz, and2.31 parts Organohydrogenpolysiloxane 1.

To 4.65 parts of Part A of the Base formulation is added 0.25 part ofUnsaturated ester functional compound 2. To 4.65 parts of Part B of theBase formulation is added 0.46 part of Fluoroorganosilicone 2. Parts Aand B are hand mixed with a microspatula, and the mixture is cast into afilm sample according to the method described in Reference Example 5.The sample is analyzed according to the methods of Reference Example 6and Reference Example 7. The results are in Tables 5 and 6 and FIG. 2.

Comparative Example 7 Composition without Fluoroorganosilicone Additive

To 4.74 parts of Part A of the Base formulation of Example 4 is added0.25 part of Unsaturated ester functional compound 2. To 4.74 parts ofPart B of the Base formulation of Example 4 is added 0.27 part ofOrganohydrogenpolysiloxane 1, an amount giving a ratio of 1 mol of SiHper mole of methacryloyloxy functionality from Unsaturated esterfunctional compound 2. Parts A and B are then hand mixed with amicrospatula, and the mixture is cast into a film sample according tothe method described in Reference Example 5. The sample is analyzedaccording to the methods of Reference Example 6 and Reference Example 7.The results are in Tables 5 and 6 and FIG. 2.

TABLE 5 Reference Example 6 Results Example 4 Free PC Interface Surface(103) Bulk (104) (105) Spot 106 107 106 107 106 107 Element F 29.3 30.33.9 4.0 12.3 12.4 O 16.3 16.2 25.5 25.5 22.4 22.7 C 44.5 43.9 48.5 48.647.5 46.9 Si 9.9 9.6 22.2 22.0 17.8 18.0 C:Si Ratio 4.5:1 4.6:1 2.2:12.2:1 2.7:1 2.6:1 Hi Res C Spectra Free PC Interface Surface (103) Bulk(104) (105) Spot 106 107 106 Spot 106 107 C1s Peak Aliphatic C 63.2 60.193.3 93.1 82.1 82.4 C—O 7.8 9.7 2.5 2.7 6.8 7.7 C═O 3.6 3.8 1.0 1.0 2.01.6 CF2 18.9 19.6 2.2 2.2 6.6 6.2 CF3 6.5 6.8 1.0 1.1 2.5 2.1Comparative Example 7 Free PC Interface Surface (103) Bulk (104) (105)Spot 106 107 106 107 106 107 Element F ND ND ND ND ND ND O 25.6 25.527.0 26.7 26.0 26.0 C 51.8 51.9 49.9 50.1 52.5 52.3 Si 22.6 22.6 23.123.2 21.5 21.7 C:Si Ratio 2.3:1 2.3:1 2.2:1 2.2:1 2.4:1 2.4:1 Hi Res CSpectra Free PC Interface Surface (103) Bulk (104) (105) Spot 106 107106 Spot 106 107 C1s Peak Aliphatic C 98.6 97.4 97.4 96.7 95.0 95.5 C—O1.4 1.8 2.1 2.4 3.3 3.0 C═O ND 0.8 0.5 0.9 1.7 1.5 CF2 ND ND ND ND ND NDCF3 ND ND ND ND ND ND ND means not detected.

TABLE 6 Reference Example 7 Results Area Example 4 Comparative Example 7Free Surface (103) —C═O 2.1 0.8 —Si—H 2.7 1.7 Bulk (104) —C═O 1.0 1.0—Si—H 1.0 1.0 Interface (105) —C═O 1.5 1.0 —Si—H 1.8 0.4

Example 4 and Comparative Example 7 demonstrate spectroscopically thatthe combination of Unsaturated ester functional compound 2 andFluoroorganosilicone 2 in an addition curing silicone matrix providesenhanced enrichment of these species at the air and plastic interfaces.Therefore, without wishing to be bound by theory, it is expected thatthe combination of the unsaturated ester-functional compound and thefluoroorganosilicone provide commensurate modification of propertiesdependent upon surface and interface composition, such as adhesion andchemical resistance.

Comparative Example 8

A composition is prepared by mixing components (A), (B), (C), and (D).Component (A) is 56.75 parts Blend 1, 0.21 parts Catalyst 1, 2.67 partsOrganohydrogenpolysiloxane 1, 0.19 parts Cure Modifier 1, 0.19 partsVoid Reducing Agent, and 0.19 parts pigment. Organohydrogenpolysiloxane1 is added in an amount such that 1.9 mol of SiH groups inOrganohydrogenpolysiloxane 1 are available per mol of Si-attachedalkenyl groups in the unsaturated polyorganosiloxane of component (A)(SiH_(B):Vi_(A) is 1.9:1).

-   -   (B) is 32.23 parts Quartz.    -   (C) is 1.42 parts Adhesion Promoter 1 and 2.37 parts Unsaturated        Ester-functional Compound 1.    -   (D) is 3.79 parts Fluoroorganosilicone 1.

The content of species having silicon-bonded hydrogen atoms and specieshaving aliphatically unsaturated groups is such that SiH_(tot)/Vi_(tot)is 0.51. Lap shear strength is tested according to the method ofReference Example 3. The results are in Table 7.

Comparative Example 9

A composition is prepared by mixing components (A), (B), (C), and (D).Component (A) is 55.83 parts Blend 1, 0.20 parts Catalyst 1, 4.25 partsOrganohydrogenpolysiloxane 1, 0.19 parts Cure Modifier 1, 0.19 partsVoid Reducing Agent, 0.19 parts Pigment. Organohydrogenpolysiloxane 1 isadded in an amount such that SiH_(B)/Vi_(A) is 3.0.

-   -   (B) is 31.71 parts Quartz.    -   (C) is 1.40 parts Adhesion Promoter 1 and 2.33 parts Unsaturated        Ester-functional Compound 1.    -   (D) is 3.72 parts Fluoroorganosilicone 1.

The content of species having silicon-bonded hydrogen atoms and specieshaving aliphatically unsaturated groups is such that SiH_(tot)/Vi_(tot)is 0.83. Lap shear strength is tested according to the method ofReference Example 3. The results are in Table 7.

Comparative Example 10

A composition is prepared by mixing components (A), (B), (C), and (D).Component (A) is 54.01 parts Blend 1, 0.20 parts Catalyst 1, 2.13 partsOrganohydrogenpolysiloxane 1, 0.23 parts Organohydrogenpolysiloxane 2,0.18 parts Cure Modifier 1, 0.18 parts Void Reducing Agent, 0.18 partsPigment. Organohydrogenpolysiloxane 1 is added in an amount such thatSiH_(B):Vi_(A) is 1.9.

-   -   (B) is 30.67 parts Quartz.    -   (C) is 1.35 parts Adhesion Promoter 1 and 2.25 parts Unsaturated        Ester-functional Compound 1.    -   (D) is 3.60 parts Fluoroorganosilicone 1 and 5.01 parts        Fluoroorganosilicone 2.

The content of species having silicon-bonded hydrogen atoms and specieshaving aliphatically unsaturated groups is such that SiH_(tot)/Vi_(tot)is 1.04. Lap shear strength is tested according to the method ofReference Example 3. The results are in Table 7.

Example 5

A composition is prepared by mixing components (A), (B), (C), and (D).Component (A) is 54.68 parts Blend 1, 0.20 parts Catalyst 1, 5.09 partsorganohydrogenpolysiloxane 1, 0.18 parts Cure Modifier 1, 0.18 partsVoid Reducing Agent, 0.18 parts Pigment. SiH_(B)/Vi_(A) is 3.7

-   -   (B) is 31.06 parts Quartz.    -   (C) is 1.37 parts Adhesion Promoter 1 and 2.28 parts Unsaturated        Ester-functional Compound 1.    -   (D) is 4.77 parts Fluoroorganosilicone 2.

The content of species having silicon-bonded hydrogen atoms and specieshaving aliphatically unsaturated groups is such that SiH_(tot)/Vi_(tot)is 1.56. Lap shear strength is tested according to the method ofReference Example 3. The results are in Table 7.

TABLE 7 Median Lap Shear Adhesion Strengths Comparative ComparativeComparative Example 8 Example 9 Example 10 Example 5 (kPa) (kPa) (kPa)Example 2 (kPa) (kPa) PA-sPS1 Uncured  96 ± 8  969 ± 68.3 2275 ± 2763146 ± 141 PA-sPS2 Uncured 175 ± 12  610 ± 222 2455 ± 317 3248 ± 297PA-sPS3 Uncured  56 ± 3 1302 ± 139.3 2068 ± 124 2188 ± 69 Al Uncured NotNot 3958 ± 359 3337 ± 227 Measured Measured Cu Uncured Not Not 4362 ±126 3978 ± 78 Measured Measured SS Uncured Not Not 3619 ± 105 4459 ± 473Measured Measured

Comparative Examples 7, 8, and 9 show that some formulations havinginsufficient SiH_(tot)/Vi_(tot) ratios have insufficient curing or havepoor adhesion to the Nylon-sPS blended plastics. Consequently, simplyadding a reactive Fluoroorganosilicone additive into any hydrosilylationcomposition does not necessarily provide adhesion to plastics andmetals.

INDUSTRIAL APPLICABILITY

The composition of this invention cures to form an adhesive. Theadhesive adheres to metals. The adhesive also adheres to othersubstrates such as plastics.

DRAWINGS

FIG. 1 shows a sample used for determination of interface compositionsby surface analysis according to the method described in ReferenceExample 5.

FIG. 2 shows representative ATR-IR spectra from each surface representedin FIG. 1 using a cured film of Example 4. Spectra are expanded in theregion of spectral interest to show key IR bands.

FIG. 3 shows an example of a package in which the composition of thisinvention is used as a die attach adhesive.

FIG. 4 shows an example of a package in which the composition of thisinvention is used as a die attach adhesive.

REFERENCE NUMERALS

-   101 polycarbonate substrates-   102 cured samples-   103 free surface-   104 bulk-   105 substrate interface-   106 spot for analysis-   107 spot for analysis-   108 spot for analysis-   300 package-   301 semiconductor die-   302 substrate-   303 die attach adhesive-   304 lead bonds-   305 encapsulant-   306 solder balls-   400 package-   401 first semiconductor die-   402 second semiconductor die-   403 first die attach adhesive-   404 substrate-   405 second die attach adhesive-   406 bonding wires-   407 bonding wires-   408 overmolding-   409 solder balls

1. A method comprising: (1) applying a composition to a substrate, and(2) curing the composition; where the composition is prepared by mixingcomponents comprising (I) a polyorganosiloxane having an average of atleast two unsaturated organic groups per molecule, where component (I)is free of fluorine atoms; (II) an organohydrogenpolysiloxane having anaverage of at least two silicon-bonded hydrogen atoms per molecule,where component (II) is free of fluorine atoms; (III) a hydrosilylationcatalyst; (IV) a fluoroorganosilicone having at least one functionalgroup reactive with component (I), component (II), or both; (V) anunsaturated ester-functional compound comprising

v) a combination thereof; where in formula i), each R¹⁸ is independentlya hydrogen atom, a monovalent hydrocarbon group of 1 to 4 carbon atoms,or CF₃, each R¹⁹ is independently a divalent organic group of 1 to 20carbon atoms, each R²⁰ is independently a hydrogen atom or a monovalenthydrocarbon group of 1 to 20 carbon atoms, in formula ii), n has anaverage value of 0 to 2 and m=4−n, each R²¹ is independently a hydroxylgroup, or CF³, each R²² is independently a hydrogen atom, a monovalenthydrocarbon group of 1 to 4 carbon atoms, or CF³, each R²³ isindependently a hydrogen atom or a monovalent hydrocarbon group of 1 to20 carbon atoms, in formula iii), each R²⁴ is independently afluoroalkyl group, an epoxy functional group, or a polyether group, eachR²⁵ is independently anoxygen-bridged monovalent organic group or acarbon-bridged carbonyl group, with the proviso that at least one of R²⁴or R²⁵ is unsaturated, in formula iv), each R²⁶ is independently amonovalent organic group or a hydrogen atom, with the proviso that atleast one R²⁶ is an aliphatically unsaturated monovalent organic groupor a hydrogen atom, and each R²⁷ is independently an oxygen atom or adivalent organic group; and (VI) an adhesion promoter.
 2. The method ofclaim 1, where the substrate comprises an epoxy, a polycarbonate, apoly(butylene terephthalate) resin, a polyamide resin, a blend ofpolyamide resin with syndiotactic polystyrene, anacrylonitrile-butadiene-styrene, a styrene-modified poly(phenyleneoxide), a poly(phenylene sulfide), a vinyl ester, a polyphthalamide, apolyimide, silicon, aluminum, a stainless steel alloy, titanium, copper,nickel, silver, gold, or combinations thereof.
 3. The method of claim 1,where the substrate comprises a metal.
 4. The method of claim 1, wherecomponent (I) comprises a polyorganosiloxane of the formula:(a) R¹ ₃SiO(R¹ ₂SiO)_(α)(R¹R²SiO)_(β)SiR¹ ₃,(b) R³ ₂R⁴SiO(R³ ₂SiO)_(χ)(R³R⁴SiO)_(δ)SiR³ ₂R⁴, or (c) a combinationthereof, where α has an average value of 0 to 2000, β has an averagevalue of 2 to 2000, each R¹ is independently a monovalent organic group,each R² is independently an unsaturated monovalent organic group, χ hasan average value of 0 to 2000, δ has an average value of 0 to 2000, eachR³ is independently a monovalent organic group, and each R⁴ isindependently an unsaturated monovalent organic group.
 5. The method ofclaim 1, where component (I) comprises an MQ resin consistingessentially of R⁵ ₃SiO_(1/2) units and SiO_(4/2) units, a TD resinconsisting essentially of R⁵SiO_(3/2) units and R⁵ ₂SiO_(2/2) units, anMT resin consisting essentially of R⁵ ₃SiO_(1/2) units and R⁵SiO_(3/2)units, an MTD resin consisting essentially of R⁵ ₃SiO_(1/2) units,R⁵SiO_(3/2) units, and R⁵ ₂SiO_(2/2) units, or a combination thereof,where each R⁵ is a monovalent organic group of 1 to 20 carbon atoms, andthe resin contains an average of 3 to 30 mole percent of unsaturatedorganic groups.
 6. The method of claim 1, where component (II) comprisessiloxane units selected from HR⁶ ₂SiO_(1/2), R⁶ ₃SiO_(1/2),HR⁶SiO_(2/2), R⁶ ₂SiO_(2/2), R⁶SiO_(3/2), SiO_(4/2), or combinationsthereof; where each R⁶ is independently selected from monovalent organicgroups free of aliphatic unsaturation.
 7. The method of claim 1, wherecomponent (II) comprises a compound of the formula:(a) R⁷ ₃SiO(R⁷ ₂SiO)_(ε)(R⁷HSiO)_(φ)SiR⁷ ₃, or(b) R⁸ ₂HSiO(R⁸ ₂SiO)_(γ)(R⁸HSiO)_(η)SiR⁸ ₂H, (c) a combination thereof,where ε has an average value of 0 to 2000, φ has an average value of 2to 2000, each R⁷ is independently a monovalent organic group free ofaliphatic unsaturation, γ has an average value of 0 to 2000, η has anaverage value of 0 to 2000, and each R⁸ is independently a monovalentorganic group free of aliphatic unsaturation.
 8. The method of claim 1,where component (III) comprises a platinum metal, a rhodium metal, or anorganometallic compound.
 9. The method of claim 1, where component (IV)comprises a compound of the formula:(a) R⁹ ₃SiO(R⁹ ₂SiO)_(τ)(R⁹R¹⁰SiO)_(φ)SiR⁹ ₃,(b) R¹¹ ₂R¹²SiO(R¹¹ ₂SiO)_(κ)(R¹¹R¹²SiO)_(λ)SiR¹¹ ₂R¹²,(c) F₃C(CF₂)_(ν)R¹³—Si—[O—Si(R¹⁴)₂(R¹⁵)]₃, (d) a resinous or branchedstructure consisting essentially of R¹⁵R¹⁴ ₂SiO_(1/2) units,CF₃(CF₂)_(ν)R¹³SiO_(3/2) units, and optionally SiO_(4/2) units, or (e) acombination thereof; where ξ has an average value of 0 to 2000, φ has anaverage value of 1 to 500, each R⁹ is independently a hydrogen atom or amonovalent organic group, with the proviso that at least one R⁹ is ahydrogen atom or an unsaturated monovalent organic group; each R¹⁰ isindependently a fluoro-functional organic group; κ has an average valueof 0 to 2000; λ has an average value of 0 to 500; each R¹¹ isindependently a hydrogen atom or a monovalent organic group, with theproviso that at least one R¹¹ is a hydrogen atom or an unsaturatedmonovalent organic group; each R¹² is independently a fluoro-functionalorganic group; each R¹³ is independently a divalent organic group; eachR¹⁴ is independently a monovalent hydrocarbon group free of aliphaticunsaturation; ν is 0 to 10; and each R¹⁵ is independently a hydrogenatom or an unsaturated monovalent organic group.
 10. The method of claim1, where component (VI) comprises a transition metal chelate, analkoxysilane, a combination of an alkoxysilane and a hydroxy-functionalpolyorganosiloxane, or a combination thereof.
 11. The method of claim 1,where component (VI) comprises an unsaturated alkoxysilane, anepoxy-functional alkoxysilane, an epoxy-functional siloxane, or acombination thereof.
 12. The method of claim 1, where component (VI)comprises an alkoxysilane of the formula R²⁸ _(μ)Si(OR²⁹)_((4-μ)), whereμ is 1, 2, or 3, each R²⁸ is independently a monovalent organic group,with the proviso that at least one R²⁸ is an unsaturated organic groupor an epoxy-functional group, and each R²⁹ is independently anunsubstituted, saturated hydrocarbon group of at least 1 carbon atom.13. The method of claim 1, where the composition further comprises (VII)a void reducing agent, (VIII) a pigment, (IX) a filler, (X) a curemodifier, (XI) a rheology modifier, (XII) a spacer, an acid acceptor, ananti-oxidant, a stabilizer, a flame retardant, a flow control additive,a reactive diluent, an anti-settling agent, a silylating agent, adesiccant, a blowing agent, or a combination thereof.
 14. The method ofclaim 1, where the composition has SiH_(tot)/Vi_(tot) of 1.05 to 5.0.15. The method of claim 1, where the method forms a product selectedfrom die attach adhesives, as lid seals, gels and encapsulants.
 16. Themethod of claim 1, where the composition is applied to more than onesubstrate in step (1).